Vehicular air conditioner

ABSTRACT

A vehicular air conditioner in which a plurality of parts comprising a refrigerant circuit are integrally provided to reduce an occupying space and reduce the number of the parts and the number of assembling steps. 
     A refrigerant circuit is provided with a cold storage internal heat exchanger having a high-pressure refrigerant storage unit through which the high-pressure refrigerant on the downstream side of a condenser flows, a low-pressure refrigerant storage unit through which the low-pressure refrigerant on the downstream side of an evaporator flows, and a cold storage material housing unit which houses a cold storage material therein. The cold storage internal heat exchanger exchanges the heat between the high-pressure refrigerant in the high-pressure refrigerant storage unit and the low-pressure refrigerant in the low-pressure refrigerant storage unit, cools the cold storage material stored in the cold storage material housing unit by means of the low-pressure refrigerant in the low-pressure refrigerant storage unit when a compressor is activated, cools the high-pressure refrigerant in the high-pressure refrigerant storage unit by means of the cold storage material housed in the cold storage material housing unit after the heat exchange with the low-pressure refrigerant of the low-pressure refrigerant storage unit, and cools the low-pressure refrigerant in the low-pressure refrigerant storage unit by means of the cold storage material housed in the cold storage material housing unit when the compressor is stopped.

TECHNICAL FIELD

The present invention relates to a vehicular air conditioner including arefrigerant circuit having a compressor, a condenser, a decompressor,and an evaporator.

BACKGROUND ART

A conventional vehicular air conditioner includes a refrigerant circuithaving a compressor, a condenser, a decompressor, and an evaporator, andcools a cabin by driving the compressor using an engine for a vehicle asa driving source.

In such a vehicular air conditioner, the refrigerant circuit is providedwith an internal heat exchanger for exchanging heat between ahigh-pressure refrigerant on the downstream side of the condenser and alow-pressure refrigerant on the downstream side of the evaporator so asto improve the cooling capacity.

When the air conditioner is applied for a vehicle including an idle-stopmechanism that detects stopping of the vehicle for waiting at trafficlights or the like and stops an engine, the drive of the compressor isstopped simultaneously with the stopping of the engine and thus arefrigerant is not delivered through the refrigerant circuit.Accordingly, the cooling cannot be continued. In order to continue thecooling while the compressor is stopped, a cold storage material isprovided in a refrigerant passage on the downstream side of theevaporator included in the refrigerant circuit, and is cooled by alow-pressure refrigerant during operation of the compressor.Furthermore, a cold storage heat exchanger is provided for cooling thelow-pressure refrigerant by the cold storage material while thecompressor is stopped, and the refrigerant is liquefied by the coldstorage material while the compressor is stopped. The time from thepoint when the compressor is stopped to the point when the pressure onthe high-pressure side of the refrigerant circuit is the same as that onthe low-pressure side is delayed, so that the cooling can be continuedfor a predetermined time (for example, see Patent Literature 1).

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Publication No. 2007-1485

SUMMARY OF INVENTION Technical Problem

The vehicular air conditioner includes many parts comprising therefrigerant circuit, such as the internal heat exchanger and the coldstorage heat exchanger. The number of the parts and the number ofassembling steps are increased, and accordingly, the large space isoccupied and the manufacturing cost is increased.

An object of the present invention is to provide a vehicular airconditioner in which a plurality of parts comprising a refrigerantcircuit are integrally provided to reduce an occupying space and reducethe number of parts and the number of assembling steps.

Solution to Problem

To achieve the object of the present invention, the vehicular airconditioner including a refrigerant circuit having a compressor, acondenser, a decompressor, and an evaporator, includes a cold storageinternal heat exchanger in the refrigerant circuit. The cold storageinternal heat exchanger includes a high-pressure refrigerant passagethrough which a high-pressure refrigerant on a downstream side of thecondenser flows, a low-pressure refrigerant passage through which alow-pressure refrigerant on a downstream side of the evaporator flows,and a cold storage material housing unit which houses a cold storagematerial. The cold storage internal heat exchanger exchanges heatbetween the high-pressure refrigerant in the high-pressure refrigerantpassage and the low-pressure refrigerant in the low-pressure refrigerantpassage, cools the cold storage material stored in the cold storagematerial housing unit by the low-pressure refrigerant in thelow-pressure refrigerant passage when the compressor is activated, andcools the low-pressure refrigerant in the low-pressure refrigerantpassage by the cold storage material when the compressor is stopped.

The high-pressure refrigerant on the downstream side of the condenser isexcessively cooled, and the low-pressure refrigerant on the downstreamside of the evaporator is liquefied when the compressor is stopped.Accordingly, a part of the cold storage internal heat exchanger servesas an internal heat exchanger and a cold storage heat exchanger.

According to the present invention, the part of the cold storageinternal heat exchanger serves as the internal heat exchanger and thecold storage heat exchanger. Thus, the space occupied by the refrigerantcircuit can be reduced, and the number of parts and the number ofassembling steps can be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a refrigerant circuit of a vehicular air conditioneraccording to an embodiment of the present invention.

FIG. 2 is a side cross-sectional view of a cold storage internal heatexchanger.

FIG. 3 is a cross-sectional view taken along the line A-A′ of FIG. 3.

FIG. 4 is a cross-sectional view taken along the line B-B′ of FIG. 3.

DESCRIPTION OF EMBODIMENTS

FIGS. 1 to 4 show an embodiment of the present invention.

A vehicular air conditioner according to the present invention isapplied for a vehicle including an idle-stop mechanism that detectsstopping of the vehicle for waiting at traffic lights or the like andstops an engine. The vehicular air conditioner includes a refrigerantcircuit 1 shown in FIG. 1.

In the refrigerant circuit 1, a commonly-known freezing cycle includinga compressor 2, a condenser 3, an expansion valve 4 as a decompressor,and an evaporator 5 is connected to a cold storage internal heatexchanger 10 for exchanging heat between a high-pressure refrigerant onthe downstream side of the condenser 3 and a low-pressure refrigerant onthe downstream side of the evaporator 5 and exchanging heat between acold storage material, and the high-pressure refrigerant on thedownstream side of the condenser 3 and the low-pressure refrigerant onthe downstream side of the evaporator 5. The compressor 2 is driven bythe engine of the vehicle. When the engine is stopped by the idle-stopmechanism, the drive of the compressor 2 is also stopped. In thevehicular air conditioner, the evaporator 5 is provided inside of an airconditioning unit in a cabin. Air that is heat-exchanged with therefrigerant in the evaporator 5 is supplied to the cabin by an airblower 5 a. The compressor 2, the condenser 3, the expansion valve 4,and the cold storage internal heat exchanger 10 are provided inside ofthe engine room outside the cabin. In the refrigerant circuit 1, HFC134ais used as the refrigerant.

The cold storage internal heat exchanger 10 is shaped like a cylinderextending in the horizontal direction. At one end side of the coldstorage internal heat exchanger 10, an internal heat exchanger 20 isprovided for exchanging heat between the high-pressure refrigerant onthe downstream side of the condenser 3 and the low-pressure refrigeranton the downstream side of the evaporator 5. At the other end side of thecold storage internal heat exchanger 10, a cold storage heat exchanger30 is provided for exchanging heat between the cold storage material,and the high-pressure refrigerant on the downstream side of thecondenser 3 and the low-pressure refrigerant on the downstream of theevaporator 5.

The internal heat exchanger 20 includes: a first cylindrical member 21;a second cylindrical member 22 provided on the lower portion of thefirst cylindrical member 21; a first closing plate 23 that closes oneends of the first cylindrical member 21 and the second cylindricalmember; and a partition plate 24 provided on the other ends of the firstcylindrical member 21 and the second cylindrical member 22 forpartitioning between the internal heat exchanger 20 and the cold storageheat exchanger 30.

The cold storage heat exchanger 30 includes: a third cylindrical member31 that houses the cold storage material therein; a fourth cylindricalmember 32 provided on the upper portion of the third cylindrical member31; a fifth cylindrical member 33 provided on the lower portion of thethird cylindrical member 31; a partition plate 24 provided on one endsof the third cylindrical member 31, the fourth cylindrical member 32,and the fifth cylindrical member 33; and a second closing plate 34 forclosing the other ends of the third cylindrical member 31, the fourthcylindrical member 32, and the fifth cylindrical member 33.

The first closing plate 23 includes a low-pressure refrigerant outlet 23a at the upper portion of the one end of the first cylindrical member21, and includes a high-pressure refrigerant inlet 23 b at the lowerportion of the one end of the second cylindrical member 22. Thepartition plate 24 includes a first communication hole 24 a at the upperportion of the other end of the first cylindrical member 21 and at theupper portion of the one end of the fourth cylindrical member 32, andincludes a second communication hole 24 b at the lower portion of theother end of the second cylindrical member 22 and at the one end of thefifth cylindrical member 33. Furthermore, the second closing plate 34includes a low-pressure refrigerant inlet 34 a at the upper portion ofthe other end of the fourth cylindrical member 32, and includes ahigh-pressure refrigerant inlet 34 b at the other end of the fifthcylindrical member 33. A high-pressure refrigerant storage unit 11,through which the high-pressure refrigerant that flows from thecondenser 3 is delivered and which can store a predetermined amount ofhigh-pressure refrigerant, is provided in the second cylindrical member22 and the fifth cylindrical member 33. A low-pressure refrigerantstorage unit 12, through which the low-pressure refrigerant that flowsfrom the evaporator 5 is delivered and which can store a predeterminedamount of low-pressure refrigerant, is provided in the first cylindricalmember 21 and the fourth cylindrical member 32. A cold storage materialhousing unit 13 is provided in the third cylindrical member 31. Coolantand water for cooling the engine as the cold storage material is housedin the cold storage material housing unit 13.

In the vehicular air conditioner as described above, the compressor 2 isdriven during traveling of the vehicle. The refrigerant discharged fromthe compressor 2 radiates heat in the condenser 3 to be liquefied, andflows through the high-pressure refrigerant storage unit 11 of the coldstorage internal heat exchanger 10. The refrigerant delivered from thehigh-pressure refrigerant storage unit 11 of the cold storage internalheat exchanger 10 is depressurized in the expansion valve 4, and absorbsheat to evaporate in the evaporator 5. The refrigerant is deliveredthrough the low-pressure refrigerant storage unit 12 of the cold storageinternal heat exchanger 10 and then is sucked into the compressor 2.

During travelling of the vehicle, the cold storage material housed inthe cold storage material housing unit 13 of the cold storage internalheat exchanger 10 is cooled by the low-pressure refrigerant flowingthrough the low-pressure refrigerant storage unit 12 via the fourthcylindrical member 32. The refrigerant flowing through the high-pressurerefrigerant storage unit 11 of the cold storage internal heat exchanger10 is excessively cooled by heat-exchange with the refrigerant flowingthrough the low-pressure refrigerant storage unit 12 via the secondcylindrical member 22, and is further excessively cooled byheat-exchange with the cold storage material housed in the cold storagematerial housing unit 13 via the fifth cylindrical member 33. Since therefrigerant liquefied in the condenser 3 is temporarily stored in thesecond cylindrical member 22 serving as the high-pressure refrigerantstorage unit 11 of the cold storage internal heat exchanger 10, therefrigerant is supplied to the evaporator 5 depending on the coolingload.

When the engine is stopped by detection of stopping of the vehicle forwaiting at traffic lights or the like and thus the drive of thecompressor 2 is stopped, the refrigerant is delivered from thehigh-pressure side to the low-pressure side until the pressure in therefrigerant circuit 1 becomes equalizing. The low-pressure refrigerantin the low-pressure refrigerant storage unit 12 of the cold-storageinternal heat exchanger 10 is cooled by the cold storage material of thecold storage material housing unit 13 and is liquefied, and accordingly,the increase of the pressure at the low-pressure side in the refrigerantcircuit 1 becomes slow. Therefore, the time required for equalizing thepressure in the refrigerant circuit 1 becomes long. Thus, even when thedrive of the compressor 2 is stopped, the cabin can be continued to becooled while the refrigerant flows in the refrigerant circuit 1.

While the drive of the compressor 2 is stopped, the refrigerant flowingthrough the low-pressure refrigerant storage unit 12 of the cold storageinternal heat exchanger 10 is cooled by the cold storage material of thecold storage material housing unit 13 to be liquefied, and remains inthe fourth cylindrical member 32 of the low-pressure refrigerant storageunit 12. When the liquefied refrigerant overflows from the fourthcylindrical member 32 of the low-pressure refrigerant storage unit 12,the overflowed liquefied refrigerant is delivered into the firstcylindrical member 21 of the low-pressure refrigerant storage unit 12and is heated by the refrigerant in the high-pressure refrigerantstorage unit 12 via the second cylindrical member 22 to be evaporated.Accordingly, the liquefied refrigerant does not flow out of therefrigerant outlet 23 a provided on the upper portion of the firstcylindrical member 21 of the low-pressure refrigerant storage unit 12.

In the vehicular air conditioner according to the embodiment, therefrigerant circuit 1 is provided with the cold storage internal heatexchanger 10 including the high-pressure refrigerant storage unit 11through which the high-pressure refrigerant on the downstream side ofthe condenser 3 flows, the low-pressure refrigerant storage unit 12through which the low-pressure refrigerant on the downstream side of theevaporator 5 flows, and the heat storage material housing unit 13 whichhouses the heat storage material therein. The cold storage internal heatexchanger 10 exchanges the heat between the high-pressure refrigerant inthe high-pressure refrigerant storage unit 11 and the low-pressurerefrigerant in the low-pressure refrigerant storage unit 12, cools thecold storage material stored in the cold storage material housing unit13 by means of the low-pressure refrigerant in the low-pressurerefrigerant storage unit 12 when the compressor 2 is activated, andcools the low-pressure refrigerant in the low-pressure refrigerantstorage unit 12 by means of the cold storage material stored in the coldstorage material housing unit 13 when the compressor 2 is stopped.Accordingly, a part of the cold storage internal heat exchanger 10 canserve as an internal heat exchanger and as a cold storage heatexchanger. Moreover, a space occupied by the refrigerant circuit 1 canbe reduced, and the number of parts and the number of assembling stepscan be also reduced.

When the compressor 2 is activated, the high-pressure refrigerant in thehigh-pressure refrigerant storage unit 11 after heat-exchange with thelow-pressure refrigerant in the low-pressure refrigerant storage unit 12is cooled by the cool storage material in the heat storage materialhousing unit 13. Accordingly, after the high-pressure refrigerant isexcessively cooled by heat-exchange with the refrigerant in thelow-pressure refrigerant storage unit 12, the high-pressure refrigerantis further excessively cooled by heat-exchange with the cold storagematerial in the cold storage material housing unit 13. Thus, theexcessive cooling of the high-pressure refrigerant can be reliablyperformed.

The cold storage internal heat exchanger 10 includes the low-pressurerefrigerant storage unit 12 through which the low-pressure refrigeranton the downstream side of the evaporator 5 flows and which can store apredetermined amount of low-pressure refrigerant, and the refrigerantoutlet 21 a of the low-pressure refrigerant storage unit 12 is providedon the upper portion of the first cylindrical member 21. Accordingly,the low-pressure refrigerant cooled by the cold storage material to beliquefied is prevented from flowing out of the low-pressure refrigerantstorage unit 12. The liquid compression by the compressor 2 can beprevented without independently providing an accumulator to therefrigerant circuit 1.

The cold storage internal heat exchanger 10 includes the high-pressurerefrigerant storage unit 11 through which the high-pressure refrigeranton the downstream side of the condenser 3 flows and which can store apredetermined amount of high-pressure refrigerant. Accordingly, therefrigerant liquefied in the condenser 3 can be temporarily stored inthe high-pressure refrigerant storage unit 11. Without independentlyproviding a liquid receiver to the refrigerant circuit 1, therefrigerant can be reliably supplied to the evaporator 5 when thecooling load is changed.

At this time, the high-pressure refrigerant in the high-pressurerefrigerant storage unit 11 after heat-exchange with the low-pressurerefrigerant in the low-pressure refrigerant storage unit 12 is cooled bythe cold storage material of the cold storage material housing unit 13.Accordingly, even when the internal capacity of the second cylindricalmember 22 is increased for storing the liquefied refrigerant in thehigh-pressure refrigerant storage unit 11, the high-pressure refrigerantcan be excessively cooled. The accumulating function and the internalheat exchanging function can be reliably obtained.

INDUSTRIAL APPLICABILITY

The present invention is widely applicable to an air conditionerincluding a refrigerant circuit having a compressor, a condenser, adecompressor, and an evaporator.

REFERENCE SIGNS LIST

1 . . . refrigerant circuit, 2 . . . compressor, 3 . . . condenser, 4 .. . expansion valve, 5 . . . evaporator, 10 . . . cold storage internalheat exchanger, 11 . . . high-pressure refrigerant storage unit, 12 . .. low-pressure refrigerant storage unit, 13 . . . cold storage materialhousing unit, 20 . . . internal heat exchanger, 21 . . . firstcylindrical member, 22 . . . second cylindrical member, 30 . . . coldstorage heat exchanger, 31 . . . third cylindrical member, 32 . . .fourth cylindrical member, 33 . . . fifth cylindrical member

1. A vehicular air conditioner including a refrigerant circuit having acompressor, a condenser, a decompressor, and an evaporator, comprising:a cold storage internal heat exchanger in the refrigerant circuit, thecold storage internal heat exchanger including a high-pressurerefrigerant passage through which a high-pressure refrigerant on adownstream side of the condenser flows, a low-pressure refrigerantpassage through which a low-pressure refrigerant on a downstream side ofthe evaporator flows, and a cold storage material housing unit whichhouses a cold storage material, the cold storage internal heat exchangerexchanging heat between the high-pressure refrigerant in thehigh-pressure refrigerant passage and the low-pressure refrigerant inthe low-pressure refrigerant passage, cooling the cold storage materialstored in the cold storage material housing unit by the low-pressurerefrigerant in the low-pressure refrigerant passage when the compressoris activated, and cooling the low-pressure refrigerant in thelow-pressure refrigerant passage by the cold storage material when thecompressor is stopped.
 2. The vehicular air conditioner according toclaim 1, wherein the cold storage internal heat exchanger is structuredto cool the high-pressure refrigerant in the high-pressure refrigerantpassage using the cold storage material after heat-exchange with thelow-pressure refrigerant in the low-pressure refrigerant passage whenthe compressor is activated.
 3. The vehicular air conditioner accordingto claim 1, wherein a low-pressure refrigerant storage unit throughwhich the low-pressure refrigerant on the downstream side of theevaporator flows and which can store a predetermined amount oflow-pressure refrigerant is provided as the low-pressure refrigerantpassage of the cold storage internal heat exchanger, and an outlet forthe low-pressure refrigerant in the low-pressure refrigerant storageunit is provided on an upper portion of the low-pressure refrigerantstorage unit.
 4. The vehicular air conditioner according to claim 1,wherein a high-pressure refrigerant storage unit through which thehigh-pressure refrigerant on the downstream of the condenser flows andwhich can store a predetermined amount of high-pressure refrigerant isprovided as the high-pressure refrigerant passage of the cold storageinternal heat exchanger.